151b adrenal cortex pathophysiology

Question 1

what hormone feedbacks to inhibit ACTH release?

Answer 1

cortisol

Question 2

what happens to excess ACTH in regards to skin?

Answer 2

processed to POMC to MSH –> skin hyperpigmentation (seen in Addison’s disease)

Question 3

what has a large role in increasing aldosterone secretion? minor role?

Answer 3

RAS system

minor role - high serum K, ACTH

Question 4

when is ACTH and cortisol production high? low?

Answer 4

high - 5 am

low - midnight

if high all the time –> cushing’s disease

Question 5

stimulatory tests - used in adrenal insufficiency
1 of 2

ACTH infusion test - normal vs steroid suppressed vs addison’s disease

Answer 5

normal - rise in cortisol

steroid suppressed - slow rise in cortisol

addison’s - no rise in cortisol

Question 6

stimulatory tests - used in adrenal insufficiency
2 of 2

Insulin tolerance test - what should rise about an injection of insulin normally?

Answer 6

GH and cortisol as a result of insulin induced hypoglycemia (stress hormones see low glucose as a threat to survival and want to raise glucose levels)

Question 7

Inhibitory tests - used in adrenal hyperfunction

dexamethasone suppression test - normal response

Answer 7

reduce ACTH and cortisol production

Question 8

difference in primary vs secondary adrenal hypofunction

Answer 8

primary - “addison’s”
All 3 cortex hormones low
high ACTH –> pigmentation

secondary - ACTH deficiency –> no pigmentation
normal aldosterone, low cortisol and androgen